Rechargeable lithium battery technology has become an important source in providing new, lightweight and high energy density batteries for many applications growing with the electronic industry. These batteries have gained increased attention because of their possible utilization for high power applications such as hybrid electric vehicles. The LixC6/Li1−xCoO2 cell is widely commercialized, and is also the best known lithium ion battery cell chemistry in which Li1−xCoO2 plays the role of the cathode or positive electrode while LixC6 acts as the anode or negative electrode. Theoretically during the charge, lithium ions can be extracted from the layered structure of LiCoO2 and then inserted into the carbonaceous structure, leading to the formation of CoO2 and Li6C the hypothetical phases. At the top of the charge, highly lithiated carbon or graphite is a very reactive material, particularly in the case of cells made of cathodes containing nickel and flammable organic electrolytes. Therefore, there is a major concern to address the issue of the safety of the cells which leads to introducing Li4Ti5O12 as an alternative to carbon.
Li4Ti5O12 has a spinel structure and can be written as Li8a[Ti1.67Li0.33]16dO4. Lithium is inserted into the structure, and then the rock-salt phase [Li2]16c[Ti1.67Li0.33]16dO4 is generated. Hence, a two-phase reaction provides a constant voltage at 1.5V versus lithium metal. A major disadvantage of a Li4Ti5O12 electrode is its insulating character because it has poor electronic and ionic conductivities, which seriously limit its utilization for high rates application as a preferred anode. As a solution, several attempts of doping this material with materials such as Mg2+, Al3+ have been reported in order to improve its electronic conductivity.